Dud comes from dudde, an early English word that means "cloak" or "mantle." How did the word's meaning change from "cloak" to "something that does not work well"? By the 1500s, "dud" had the meaning "ragged clothing." In the 1800s, it was used for "a person in ragged clothing." Then, in the early 1900s, people began to use "dud" as a word for a useless person or thing. During World War One, a shell that did not explode was a "dud." Since then, its meaning has widened to include any bad item in a batch.